1. Field of the Invention
The invention relates to a mounting structure of a motor generator for an internal combustion engine in which the motor generator is attached to an engine body of the internal combustion engine and coupled to and driven by the output thereof. More particularly, the invention relates to such a mounting structure for which a tensioner, which applies tension to a power transmission belt coupled to the internal combustion engine, is attached to the motor generator.
2. Description of the Related Art
Art is known in which the output of an engine is utilized to drive a water pump, an air conditioner compressor, an alternator, and the like. Moreover, a motor generator is sometimes adopted in place of an alternator, and used to provide torque assistance. In this case, the motor generator is driven by the output of the engine instead of the alternator.
FIG. 3 shows a known motor generator mounting structure e of this type. A pulley 12 is provided on an engine block 10 and rotated by a crank shaft of the engine.
In addition, a water pump 14 is provided on one side of the engine block 10 (more specifically, the right side as shown in FIG. 3). The water pump 14 is a coolant pump that uses rotation of a pulley 16 to circulate coolant to the engine and a radiator (not shown).
A motor generator 18 is disposed next to the water pump 14. The motor generator 18 uses torque of the engine to generate electricity for recharging a battery (not shown), and, in addition, assists engine output torque when necessary by rotating an output shaft of the engine (namely, the crank shaft). The motor generator 18 has a rotating shaft to which a pulley 20 is attached. Moreover, an air conditioner compressor 22 is disposed near to the water pump 14 and the motor generator 18. The compressor 22 is driven by a pulley 24.
A belt 26 is wound around the pulleys 12, 16, 20 and 24. Accordingly, driving force of the pulley 12 is used to drive the water pump 14, the motor generator 18, and the compressor 22.
Note that, in order to transmit driving force it is essential that the belt 26 is pressed against the pulleys 12, 16, 20 and 24 so that it does not slip. To achieve this, a tensioner 28 is provided that applies tensioning force (tension) to the belt 26.
The tensioner 28 includes a body 34, and a pair of rollers 36a and 36b. The pair of rollers 36a and 36b apply tension to the belt 26 by pressing the outer sides thereof. The tensioner 28 is fixed at one side to a boss of the engine block 10 using a bracket 38a, and at the other side to an external wall of the water pump 14 using a bracket 38b. 
In the previously described structure, provision of the tensioner 28 enables a desired amount of tension to be applied to the belt 26. Accordingly, driving force can be reliably transmitted using the belt 26.
Note that, the tensioner 28 is highly versatile, and may be used with various different types of engines. However, in the case of another engine, the position of the boss to which the tensioner can be fixed is different, and thus it is necessary to manufacture a bracket to match. Moreover, if a suitable boss is not provided on the engine block, it is necessary to make changes to the engine block itself.
It should be noted that there are various ways in which tensioners can be fitted to an engine. For example, Japanese Patent Laid-Open Publication No. 2003-201857 discloses a configuration in which a tensioner is attached to an oil pump that is driven by an engine via a chain. The tensioner applies tension to the chain.